A network is made up of a series of nodes interconnected by communication paths. Networks often interconnect with computing devices of differing types and with other networks of various sizes. An enterprise network, for example, may interconnect with several local area networks (LANs) and one or more metropolitan area networks (MANs) or wide are networks (WANs).
In practice, many large networks with broad geographic coverage, like the Internet, are made by connecting some of the nodes on one network with nodes of another network. This intermingling of network assets actually helps create the broader network. Occasionally, some of the intermingled assets are part of a managed network as opposed to the public Internet.
A given network may be characterized by several factors like who can use the network, the type of traffic the network carries, the typical nature of the network's connections, and the transmission technology the network uses. For example, one network may be public and carry circuit switched voice traffic while another may be private and carry packet switched data traffic. Whatever the make-up, most networks facilitate the communication of information between at least two nodes, and as such act as communications networks.
A difficulty may arise, however, when users on one network attempt to communicate with a user on another network. Communication across the boundaries of the two networks may create challenges. For example, while one managed network operator may be able to offer packetized voice services between users on its network, the same operator may find it more difficult to allow internetwork voice calls. Often these calls are actually carried on a circuit switched telephone network, which, in many cases, requires the calls to be translated from a packetized format like voice over internet protocol (VoIP) to a time division multiplexed (TDM) format.